NORMAL ANATOMY OF THE LIVER. 



167 



omentum, and which accompanies them along 

 the portal canals and interlobular fissures to 

 their ultimate distribution in the substance of 

 the lobules. It forms for each of the lobules a 

 distinct capsule which invests it on all sides 

 with the exception of its base, and is then ex- 

 panded over the whole of the exterior of the 

 organ, constituting the proper capsule of the 

 liver. Glisson's capsule serves to maintain the 

 portal vein, hepatic artery, and hepatic ducts in 

 connection with each other, and attaches them 

 also to the surface of the portal canals; it con- 

 nects the trunks of the hepatic veins to the 

 surface of the canals in which they run ; it sup- 

 ports the lobules and binds them together, and 

 by its exterior expansion it invests and protects 

 the entire organ. But Glisson's capsule, ob- 

 serves Kiernan, " is not mere cellular tissue ; 

 it is to the liver what the pia mater is to the 

 brain; it is a cellulo-vascular membrane, in 

 which the vessels divide and subdivide to an 

 extreme degree of minuteness ; which lines the 

 portal canals, forming sheaths for the larger ves- 

 sels contained in them, and a web in which the 

 smaller vessels ramify ; which enters the inter- 

 lobular fissures, and with the vessels forms the 

 capsules of the lobules, and which finally enters 

 the lobules, and with the bloodvessels expands 

 itself over the secreting biliary ducts. Hence 

 arises a natural division of the capsule into three 

 portions, a vaginal, an interlobular, and a lobu- 

 lar portion." 



The vaginal portion of the capsule is loose 

 and abundant ; it occupies the portal canals 

 and incloses the portal vein, hepatic duct, and 

 hepatic artery. In the larger canals (Jig. 36, 

 8,) it completely surrounds these vessels, but 

 in the smaller ones (Jig. 37,) is situated only 

 on that side of the portal vein upon which 

 the duct and artery are placed, the opposite side 

 of the vein being in contact with the capsular 

 surfaces of the lobules. It constitutes a me- 

 dium for the ramification of the vaginal plexus 

 formed by the vein, artery, and duct, previously 

 to their entrance into the cellular interval of the 

 interlobular fissures. 



The interlobular portion forms the cellular 

 capsule for each of the lobules and the bond of 

 union between their contiguous surfaces. It 

 supports the plexiform ramifications of the por- 

 tal vein, hepatic artery, and duct, and is the 

 medium of vascular communication between 

 all the lobules of the liver. 



The lobular portion forms sheaths for the 

 minute vessels which enter the lobules, and a 

 cellular parenchyma for the substance of those 

 bodies. 



The portal vein is formed by the union of the 

 venous trunks which return the blood from the 

 chylopoietic viscera, viz., the superior and in- 

 ferior mesenteric, the splenic, and gastric veins. 

 Commencing behind the pancreas where all 

 these veins converge, the portal trunk ascends 

 along the right border of the lesser omentum, 

 lying behind the hepatic artery and ductus com- 

 munis choledochus to the transverse fissure. 

 At the transverse fissure it bifurcates into two 

 trunks which enter the right and left lobes, 

 and divide and subdivide as they take their 



course through the portal canals, until they are 

 ultimately lost in the substance of the lobules. 

 The branches of the portal vein are accompanied 

 throughout their course by branches of the hepatic 

 duct and hepatic artery, and they are inclosed 

 and connected to the capsular surfaces of the 

 lobules forming the portal canals, by Glisson's 

 capsule. The branches of the portal vein are 

 divisible into vaginal, interlobular, and lobular. 

 The vaginal branches (Jig 36, 3, Jig. 38, f) 

 are the small veins which are given off by the 

 portal trunks during their passage through the 

 portal canals, and which are intended to convey 



Fig. 36. 



A transverse section of a large portal canal and it* 

 vessels. The lobules are in a state of general con- 

 gestion, their central portions being more congested 

 than their marginal portions. Prom Kiernan'i 

 paper. 



No. 1, Superficial lobules forming theparietes of 

 the canal. In some the intra-lobular veia does not 

 extend to the surface of the canal ; this appearance 

 depends upon the direction in which the incision is 

 made. 2, The portal vein. 3, Vaginal branches 

 arising from the vein and dividing into interlobular 

 branches which enter the interlobular spaces. 

 4, Hepatic duct. It is seen to give off vaginal 

 branches which divide into interlobular ducts, the 

 latter enter the interlobular spaces. 5, The hepatic 

 artery ; it is seen giving off vaginal branches which 

 divide into interlobular branches, and the latter 

 enter the spaces with the branches of the portal 

 vein and hepatic duct. 6, Three interlobular ves- 

 sels, a duct, vein, and artery, entering each inter- 

 lobular space. 7, A part of the vaginal plexus. 

 8,8, Glisson's capsule, which completely surrounds 

 the vessels. 



their blood into the substance of the lobules. 

 In the cellular sheath of Glisson's capsule which 

 surrounds the portal vein, they inosculate freely 

 with each other and form, together with the va- 

 ginal branches of the duct and artery, a vascu- 

 lar plexus, named from its situation the vaginal 

 plexus. This vaginal plexus establishes a com- 

 munication between the vaginal veins through- 

 out the portal canals, and serves to equalise the 

 supply of blood to the lobules. Opposite each 

 interlobular space an interlobular vein is given 

 ofT, which enters between the lobules and rami- 

 fies in the interlobular fissures. In the larger 

 portal canals (Jig. 36,) the vaginal plexus com- 

 pletely surrounds the portal vein, hepatic duct 



